Finally took the forks out and made some changes.
When you start to pull the caps off, you'll notice that there is a bunch of glue flaking off, try not to get this down into your forks. Note the amount of pre-load in the spring.
After unscrewing the cap, you can see the spring placement.
I poured about 6.5 ounces of oil out, so I started my testing by putting 6.5 ounces of Lucas 20 weight fork oil back in.
That oil poured out like water compared to the 20 weight. When you are draining the old oil, you'll need to pump the damper rod in and out a few times to make sure you get all the oil out. When adding the new fluid, you'll also need to pump the damper to make sure the air gets ejected.
After the oil was added, I spent some time trying to get some additional pre-load on the springs. This was pretty easy by just adding some washers, added a bit more than half an inch of reload.
Hopefully that preload isn't too much to cause coil bind, but it should be fine.